Cataract and systemic diseases

Congenital cataracts can accompany many systemic diseases in children.

The overwhelming majority are extremely rare and are of interest to ophthalmologists-pediatricians. However, general ophthalmologists should be familiar with the following conditions.

[1], [2], [3]

Symptoms of the cataracts in systemic diseases

[4], [5], [6]

Diseases of metabolism and cataract

1. Galactosemia includes severe disorders of galactose uptake caused by the absence of the galactose-1-phosphaturidyl transferase enzyme. The inheritance is autosomal recessive.
   • to systemic disorders that occur in early childhood include stunted growth, apathy, frequent vomiting and diarrhea. Decay products are found in the urine after drinking milk. If products containing galactose are not excluded from the diet, hepatosplenomegaly develops, kidney damage, anemia, deafness, mental retardation, leading to death;
   • Cataract characterized by central opacities in the form of "droplets of fat" develops during the first days or weeks of life in most patients. Elimination of galactose (dairy products) from the diet prevents cataract progression, and sometimes lens changes can be reversible.
2. Deficiency of galactokinae includes disorders of the a chain of metabolism of galactose (the first enzyme). The inheritance is autosomal recessive.
   • systemic disorders are absent, despite the presence of decay products in the urine after drinking milk;
   • Cataracts consisting of lamellar opacities can develop intrauterine or after birth. Some presenile cataracts also develop as a result of a deficiency of galactokinase. Galactose is an indirect cataractogenic agent that is the source of dulcitol (a product of the breakdown of galactose) inside the lens. The accumulation of dulcitol in the lens increases the intra-ophthalmic osmotic pressure, leading to excessive content of oxen, rupture of lens fibers and opacities.
3. Lowe syndrome (oculocerebral) is a rare congenital disorder of amino acid metabolism, which affects mainly boys. Inheritance is X-linked.
   • systemic disorders and key to mental retardation, Fanconi syndrome of proximal renal tubules, muscle hypotension, frontal bone prominence and sunken eyes. This is one of the few conditions in which a combination of congenital cataracts and glaucoma is possible;
   • Cataract is special, the lens is small in size, is thin, has the shape of a disk (microfakia), a posterior lentiglobus is possible. Cataract can be capsular, lamellar, nuclear or total. Carrying in women is characterized by small-point cortical opacities of the lens, usually not affecting visual acuity;
   • Congenital glaucoma occurs in 50% of cases.
4. Other disorders include hypoparathyroidism, pseudohypoparathyroidism.

[7], [8], [9], [10], [11], [12]

Intrauterine infections and cataracts

1. Congenital rubella is accompanied by cataracts in about 15% of cases. After 6 weeks of gestation, the capsule of the lens is impervious to the virus. Opacification of the lens (which can be either unilateral or bilateral) often occurs at birth, but can develop in a few weeks or even months. Dense pearly opacities can cover the nucleus or settle diffusely throughout the lens. The virus is able to persist on the lens for 3 years after birth.
2. Other intrauterine infections that may be accompanied by neonatal cataracts are toxoplasmosis, cytomegalovirus, herpes simplex virus and chicken pox,

Chromosomal abnormalities and cataracts

1. Down syndrome (trisomy 21)
   • systemic disorders: mental retardation, narrow slanting eyes, epicanthus, flat face with characteristic prognathism, brachycephaly with a flattened occiput, broad palms and short arms, sticking out tongue;
   • Cataracts of different morphologies occur in about 5% of patients. The opacities are usually symmetrical and often develop in late childhood.
2. Other chromosomal abnormalities accompanied by cataracts: Patau syndrome (trisomy 13) and Edward syndrome (trisomy 18).
3. The syndrome of Hallermann-Streiff-Francois is a rare disease.
   • systemic disorders: protruding forehead, small "bird's nose", baldness, micrognathia and pointed chin, short stature and hypodontia;
   • Cataract, which can be pleated, is found in 90% of cases.
4. The Nance-Horan syndrome has an X-linked type of inheritance.
   • systemic disorders: additional incisors, prominirutous, anterior ears turned up, small metacarpal bones;
   • Cataracts can be dense with an inordinate microphthalmos. In female carriers, tender opacities in the seam area are possible.

[13], [14], [15], [16]

Diagnostics of the cataracts in systemic diseases

In the neonatal period, the definition of visual acuity is impossible, therefore, an assessment of the density and morphology of opacities, other concomitant eye symptoms and visual behavior of the child, determining the degree of cataract influence on vision,

Density and possible influence on visual functions are assessed on the basis of the appearance of a reflex from the fundus and the degree of its visualization with direct and indirect ophthalmoscopy. The examination of newborns was simplified with the introduction of high-quality portable slit lamps. A detailed evaluation of the anterior segment is possible with limited movements of the child's head. Ophthalmoscopically, the density of cataracts is divided into:

• Very dense cataract, covering the pupil, in which it is impossible to examine the fundus; the decision on the operation is beyond doubt.
• A less dense cataract, in which it is possible to examine the retinal vessels only with the help of indirect ophthalmoscopy. Other characteristics include central or posterior-capsular opacities of more than 3 mm in diameter.
• Minor opacities, in which the examination of the retinal vessels is possible with the help of direct and indirect ophthalmoscopy. Other characteristics include central opacities of less than 3 mm in diameter and peripheral, anterior-capsular or point clouding with penetration into the transparent zones of the lens.

The morphology of opacities is key in determining etiology, as described previously.

Concomitant ocular pathology may include anterior segment (corneal opacity, microphthalmos, glaucoma, persistent hyperplastic primary vitreous humor) or posterior segment (chorioretinitis, Leber amaverz, rubella retinopathy, fovea or optic nerve hypoplasia). An examination with general anesthesia and a series of follow-up examinations to assess the extent of cataract progression or concomitant disease are necessary.

Other indicators of significant reduction in vision: the absence of central fixation, nystagmus and strabismus. With nystagmus, the prognosis for vision is poor.

Special surveys and visual evoked potentials provide additional useful information, but one should not limit oneself to them only.

System inspection

When establishing the hereditary nature of cataracts, the complex of examination of a newborn with a bilateral process should include the following:

1. Serological tests for the detection of intrauterine infection (TORCH-toxoplasmosis, rubella, cytomegalovirus and herpes simplex). If a history of rash during pregnancy, titration of antibodies against chicken pox and shingles is shown.
2. Urine. Urine analysis for reduced galactose content after milk intake (galactosemia) and chromatography for the detection of amino acids (Lowe syndrome).
3. Other studies: detection of excess blood glucose, serum calcium and phosphorus, galactose-1-phosphaturidyl transferase and galactokinase in erythrocytes.
4. The direction to the pediatrician is reasonable in cases of dysmorphism or suspected other systemic diseases. In such cases it is useful to carry out chromosome analysis.

[17], [18]

Treatment of the cataracts in systemic diseases

The definition of the timing of the operation is an important step, while the following should be guided:

1. Bilateral dense cataracts require early intervention (within 6 weeks after birth) in order to avoid the development of amblyopia. If opacities are asymmetrical, first of all the worst eye operates.
2. Bilateral partial cataract does not require surgery if it is stable. In case of doubt, a reasonable solution is to postpone surgery and monitor opacities and visual functions; Interference is indicated when a decrease in vision is detected.
3. One-sided dense cataract requires urgent surgery (for several days) followed by active treatment of amblyopia, but even so, the results are disappointing. In detecting cataracts at 16 weeks after birth, surgery is impractical due to irreversible amblyopia.
4. One-sided partial cataracts usually do not require surgical intervention. Recommended dilated pupil and contralateral gluing of the eye to prevent amblyopia.

It is important to correct the accompanying abnormal refraction.

Technique of operation

1. A scleral tunnel with a width of 6 mm is formed.
2. Introduce keratom into the anterior chamber (usually 3 mm wide) and fill it with viscoelastic.
3. Perform anterior capsulorhexis. In children, the anterior capsule is more elastic than in adults, which complicates the capsulorhexis process.
4. Aspirate the remains of the lens with vitreotome or Simcoe cannula.
5. Then capsulorhexis is produced on the posterior capsule.
6. Partial anterior vitrectomy is performed.
7. Implant if necessary posterior chamber intraocular lens from PMMA in a capsule bag.
8. For patients with a concomitant hyperplastic primary vitreous body, microsurgical scissors and tweezers may be required to remove dense capsular material or retroentulicular opacities. Sometimes there is a need for intraocular bipolar cauterization (cauterization) of bleeding vessels.
9. With a successfully formed scleral tunnel, no overlap is required.

Cataract surgery in children

Cataract surgery in children is associated with more frequent complications "than in adults.

1. The turbidity of the posterior capsule is quite often observed. It is most significant in young children due to the danger of developing amblyopia. If the anterior vitrectomy is not performed, the opacification of the vitreous front surface may occur regardless of the capsulorhexis produced. The probability of clouding is less when combined posterior capsulorhexis with vitrectomy.
2. Secondary films are formed across the pupil, especially in the eyes with microphthalmic or concomitant chronic uveitis. With insufficiently vigorous therapy of postoperative fibrinous uveitis, the probability of film formation is high. Delicate films are dissected by an NchYAG laser; at more dense - operation is required.
3. Proliferation of the epithelium of the lens is common, but usually does not affect vision if it is located outside the optical base. It is encapsulated between the remnants of the anterior and posterior capsule, known as the Soemrnerring ring.
4. Glaucoma can develop after some time in about 20% of cases.
   • Closed-angle glaucoma can appear immediately after surgery in the eyes with a microphthalmic as a result of the pupillary block.
   • Secondary open-angle glaucoma can develop years after the operation, therefore, a constant monitoring of intraocular pressure for several years is very important.
5. Detachment of the retina is rare, it is attributed to late complications.

[19], [20], [21], [22], [23]

The operation in newborns and young children

At present, the difficulties associated with the technique of performing a cataract operation in newborns and young children are basically resolved, but the results on vision remain disappointing due to the rapid development of amblyopia and its irreversibility. With regard to the optical correction of aphakic eyes in children, two factors are taken into account: the age and laterality of aphakia.

1. Points are prescribed for older children with bilateral aphakia, but not monolateral (due to possible anisometropia and aniseukonia). In newborns with bilateral aphakia, glasses are inconvenient because of their severity, unpleasant sensations, prismatic distortion and narrowing of the field of vision.
2. Contact lenses provide the best result in terms of vision, both in mono- and in bilateral aphakia. In children older than 2 years, there are problems and inconveniences when wearing, because the child becomes active and independent. The contact lens can be displaced or lost, which increases the risk of developing amblyopia. With bilateral aphakia, the way out of the situation is the appointment of glasses, whereas with monolateral aphakia, the implantation of the intraocular lens is more appropriate.
3. Implantation of the intraocular lens in young children and even newborns is being used increasingly, in certain cases it is quite effective and safe. Knowing the degree of the hypothetical shift appearing in the developing eye, in combination with precise biometrics, allows calculating the strength of the intraocular lens with regard to primary hypermetropia (corrected by glasses), and with age, refraction approaches emmetropic. However, the final refraction varies and it is impossible to guarantee emmetropia in the older age.
4. Closing the eye to treat or prevent amblyopia is ineffective.